The present invention relates to a color linear charge coupled device for an image pickup apparatus, and, more particularly, to a color linear charge coupled device (CCD) for improving color resolution by reducing the distance between the respective pixels, and a method of driving the same.
A conventional color linear CCD will be described with reference to FIG. 1, a schematic diagram of the conventional color linear CCD.
Each row of the CCD includes photo diode arrays 1, 2 and 3; transfer gates 5 positioned at both sides of photo diode arrays 1, 2 and 3; horizontal charge coupled device (HCCD) shift registers 4 surrounding the outer side of transfer gates 5; a floating diffusion element (FD) 7 positioned at one side of each CCD array; and a sensing amplifier 8 connected to FD 7.
The operation of the conventional color linear CCD will now be described. When transfer gate 5 is turned on, signal charges photoelectrically converted in each photo diode of the respective photo diode arrays 1, 2 and 3 move through their transfer gates 5 and to HCCD shift registers 4. The signal charges are moved either to their upper HCCD shift register or to their lower HCCD shift register based on the position of the charges' photodiode. In particular, the charges are moved in a zigzag manner such that charges from odd numbered photodiodes move to their upper HCCD shift register and charges from the even numbered photodiodes move to their lower HCCD shift register (or vice-versa).
Subsequently, the charges in the shift registers are moved to the right by clock signals applied to HCCD shift registers 4 so that the signals can be sensed and extracted by FD 7 and sensing amplifier 8.
In summary, the red, the green and the blue linear CCD arrays have the same configuration and operate in the same manner, except for their color. Thus, the conventional color CCD requires two HCCDs, one FD, and one sensing amplifier for each row that senses a color--a less than compact design, which therefore increases the expense of the CCD. Also, because two transfer gates and two HCCDs are positioned in the spaces between the red, green, and blue CCD rows, the physical space between the respective CCD rows is large, thus deteriorating vertical color resolution.